Process for the carbonization of wool

ABSTRACT

A device having a plurality of treatment units for carrying out the continuous carbonization of wool, comprising first means for acidifying the wool including first conveying means, comprising sieve drum means subjected to a suction draft wherein the treatment liquid is drawn from the outside to the inside of the drum, extraction means operatively connected  behind said first means for extracting acid from the wool, first drying means operatively connected behind said extraction means for drying the wool and effectively subdivided into a drying zone and into a baking zone, removing means operatively subdivided into a drying zone and into a baking zone, removing means operatively connected behind said drying means for removing the carbonized matter from the wool, and neutralizing means forming at least one neutralizing bath for neutralizing the acid remaining within said wool, said neutralizing means being operatively connected behind said removing means.

, Nov. 3,1970 H. FLEISSNER ETAL 3,537,810

PROCESS FOR THE CARBONIZATION OF WOOL 2 Sheets-Sheet 1 Filed April 1..1966

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United States Patent Office PROCESS FOR THE CARBONIZATION OF WOOL HeinzFleissner and Gerold Fleissner, Egelsbach, near Frankfurt am Main,Germany, assignors to Anstalt fur Patentdienst, Vaduz, LiechtensteinFiled Apr. 1, 1966, Ser. No. 539,529

Claims priority, application Germany, Apr. 10, 1965,

A 48,926; Oct. 14, 1965, A 50,486 Int. Cl. D06c 7/04 US. Cl. 8-140 14Claims ABSTRACT OF THE DISCLOSURE The present disclosure is directed toa process and apparatus for the continuous carbonization of wool,preferably in the form of flock, comprising the steps of wetting thewool with an acid solution, thereafter extracting, drying and heatingthe wool to a baking temperature, subsequently removing carbonizedmatter from the wool and thereafter neutralizing the acid adhering tothe fibers of the wool, at least some of the treatment media used in theaforementioned steps being applied to the wool by means of a suctiondraft.

The present invention relates to a process and a device for thecontinuous carbonization of wool, preferably of wool flock, in whichprocess the wool is wetted with acid, preferably with sulphuric acid,extracted, dried and heated to a baking temperature, subsequently openedand/or beaten, and in which process the acid adhering to the wool fibersis then neutralized. The present invention is applicable to various woolprocessing stages, i.e., to raw wool, to top, to yarn, and to piecegoods.

Carbonization is the treatment of the wool with an acid, especially withsulphuric acid, at elevated temperatures, in order to destroy vegetablecontaminations such as burrs, shives, cotton and staple fibers, andother cellulosic products so that they can be better removed from thewool.

Known processes for the carbonization of wool consist of the followingprocessing stages:

(1) Immersion of the wool into an acid bath for -30 minutes so thatthere is suflicient time for the acid to deposit on the cellulosicmatter. In general, a 3-6% sulphuric acid solution is used as acidliquor.

(2) Extraction and drying of the wool for the condensation of the acidand for the hydrolysis of the cellulosic matter.

(3) Baking, i.e., heating of the Wool to 100-120 C. for dehydration andcarbonization of the cellulosic matter whereby the baking time amountsto approximately minutes.

(4) Breaking up and removal of the charred cellulosic matter by openingor beating the wool.

(5) Neutralization and removal of the acid as well as scouring of thewool in a scouring bath, generally followed by:

(6) Drying of the Wool. This drying process can be omitted if the woolis dyed or finished by a wet treatment afterwards.

For acidifying the wool in flock form, so-called leviathan washingmachines are known in which the wool is transported through the acidliquor by means of rakes which immerse into the acid liquor. Since therequired residence time in the acid liquor amounts to 15-30 minutes,extremely long and expensive acid baths are required as well as acorrespondingly high number of rakes for the transportation of the woolthrough the acid bath.

For drying and baking the wool, drum dryers or belt dryers are used. Forremoving the charred cellulosic matter, various units can be used, forexample, openers, beating machines, carding machines and the like.

3,537,810 Patented Nov. 3, 1970 For the subsequent neutralization of theloose wool, again leviathan washing machines are used or, in the case ofpiece goods, the usual roller washing machines are used for acidifyingas Well as for neutralizing. For the final drying, again belt or drumdryers, especially sieve drum dryers, are used.

In spite of the use of auxiliary agents, the aforementioned relativelyextended treatment times are required for a good Carbonization of thewool in the known devices. Without the use of wetting agentsimpregnating times of l-2 hours are necessary. By a reduction of thetreatment time, especially of the impregnating time, to 15-30 minutes,the turn-out of the material, i.e., the wool quality, could beessentially improved..HoWever, also with these treatment times there aresuflicient detrimental effects which cause, in particular, a varying dyeaffinity and which result in considerable strength losses of the woolfibers.

The present invention has the object to eliminate the aforementioneddisadvantages by reducing the treatment times, especially theimpregnating time, and the time from acidifying to neutralizing, i.e.,the total time during which the acid reacts on the wool.

In accordance With the present invention it has been found that shortertreatment times can be obtained by a more intense mass transfer, e.g.,by more intense wetting and quick drying of the wool and of thecellulosic matter in the wool. In accordance With the present inventionit is, therefore, proposed to pass the various treatment media throughthe wool by means of a suction draft since thus the best mass transferis ensured. In further developing this object of the present invention,it is proposed to use at least one suction drum bath for wetting theWool.

Surprisingly tests have shown that when using a suction drum bath awetting time, i.e., an acidifying time, of about seconds is suificientin order to obtain, after squeezing and drying and baking in'sieve drumdryers working with a suction draft, a good carbonization and thusdestruction of the cellulosic matter. This extreme reduction of thetreatment time is most astonishing. A clear explanation is stillmissing. The phenomenon might possibly be explained by the fact thatlarge quantities of acid are brought up to the cellulosic matter by thesuction draft and that the cellulosic matter is enriched with acid muchmore rapidly when a sufficiently large amount of acid is brought up thanwas assumed up to now. Also it has been found that with these shortacidifying times, essentially less acid is deposited on the wool. Thismeans considerably smaller strength losses of the wool and lowerchemical costs, since less acid and smaller amounts of alkalis for theneutralization are required.

By the use of the known sieve drum dryers for drying and baking, alsothe drying and baking times could be significantly reduced, e.g., to 3-5minutes. I

According to another object of the present invention it is proposed tocool the acid bath down to a temperature below 20 C. Preferably the acidbath should have a temperature of 10-l5 C. It has been found that withsuch low temperatures the Wool combines with much smaller quantities ofacid whereas the acid absorption of the cellulosic matter which is to becharred does practically not decrease. The aforementioned advantagesapply here to an even greater extent.

According to another object of the present invention it is proposed topass the wool through a gas or steam atmosphere which is enriched withor consists of neutralizing agents for the neutralization of the acidadhering to the fibers after baking.

In another embodiment of the present invention it is also possible tospray the neutralizing agent onto the wool when the wool enters theneutralizing zone and to maintain a temperature in the neutralizing Zoneat which temperature the neutralizing agent is essentially evaporatedand volatilized. By the use of the suction draft by means of which thetreatment medium is sucked through the wool, according to the presentinvention, an equal distribution of the medium amongst all wool fibersis effected and thus a completely uniform and good neutralization of theacid adhering to the wool.

Uniform neutralizationis favored in the case of this last-mentionedembodiment of the present invention if the neutralizing zone is providedwith a device which ensures a constantly uniform gas concentration of agaseous neutralizing agent. This device may simply consist of, e.g., ameasuring instrument which measures the gas concentration and whichcontrols a regulating valve of a gas feed line according to therespective, preset gas concentration. If a spraying device is providedin the neutralizing zone, the neutralizing liquid is controlled in thesame way.

In general, the neutralized chemicals form a white powder which can beeasily removed from the wool during the subsequent opening or beatingprocess.

For the continuous carbonization of wool it is suggested to use a devicewhich, according to the present invention, consists of at least onesuction drum bath with an extraction device, preferably a squeezing unitconnected behind the bowl, of a dryer, preferably a sieve drum dryerwhich is subdivided into a drying zone and into a baking zone, of anopening and/or beating machine behind which are connected at least oneneutralizing bath and preferably a dryer, as well as of conveyingelements between the individual treatment devices for the continuoustransportation of the wool through the device.

It has been found that, e.g., a device consisting of the following unitswas particularly expedient and favorable for the carbonization of loosewool:

A sieve drum scouring bowl for wetting the wool. That bowl is filledwith cold, chemically neutral fresh water.

A squeezing unit at the end of that bowl for squeezing out the liquid.

A further sieve drum scouring bowl for acidifying the wool, and behindthat bowl two pairs of squeeze rollers for obtaining an as high aspossible squeezing effect. However, instead of one or two pairs ofsqueeze rollers also a continuously operating hydro-extractor may beused.

A sieve drum dryer with a predrying chamber, a drying chamber, and abaking chamber and possibly a neutralizing chamber.

Or instead of the neutralizing chamber two sieve drum bowls, onecontaining a neutralizing liquor, e.g., a soap bath with sodiumcarbonate, and the second containing chemically neutral water forwashing out the residues of the chemicals.

A sieve drum dryer for the final drying of the wool.

In general, it is of advantage if all treatment units with the exceptionof the opening and/or beating unit, work with conveying elements whichare subjected to a suction draft, preferably with sieve drums.

Furthermore, it is of advantage, if the material is extracted as far aspossible before the combined drying and baking process takes place,since in the case of a good extraction less acid is deposited on thewool fibers and since detrimental effects of the acid on the wool fibersduring the drying and making process are thus reduced. If a particularlygentle treatment of the wool is desired, it is recommended to use acontinuous hydroextractor after acidifying.

An essential advantage offered by the sieve drum dryer as compared witha belt dryer is, apart from the better drying capacity, the fact thatsoiling is much reduced. A pronounced disadvantage of the belt dryer isthat it must be stopped after a relatively short period of operation forcleaning.

Tests have shown that the quick soiling of such dryers can be avoided ifthe fiber fleece is consolidated before or at least when being depositedon the conveyor belt. Since the drying capacity depends solely on theair penetrating the fibrous material, the consolidation of the fibrousmaterial does not mean a capacity decrease as was expected up to now.

In the case of longer treatment paths, i.e., in the case of longerconveyor belts, it has been found advantageous if the fiber fleece isconsolidated during the drying process once or several times.

Fiber fly and thus a contamination of the belt dryer can be avoidedparticularly well if the fiber fleece is held to the conveyor belt bymeans of a suction draft and if it is consolidated at the same time.

Furthermore, it is of advantage if the fiber fleece is exposed toessentially higher drying temperatures in the predrying zone than in thedrying zone proper. The drying temperature in the predrying zone may beso high that the fibers in a dry condition would be damaged by that hightemperature. However, by the extraction of the moisture, the temperaturein the fiber fleece is essentially lower than the air temperature sothat fiber damage does not occur.

In the case of a belt dryer with at least one conveyor belt and onedevice for circulating the treatment medium, one or several rollers ordrums may be correlated to the conveyor belt which rollers or drumsconsolidate the fiber fleece or which, e.g., press against the fiberfleece.

According to the present invention the treatment chamber is designed inthis device as a suction chamber with the suction draft directeddownwards for consolidating and holding the fiber fleece onto theconveyor belt and/ or the conveyor belts. The suction draft may, e.g.,be formed in such a way that below the lower conveyor belt one orseveral fans with one-sided air discharge are provided, preferably foreach treatment zone, and that the fan chamber is separated from thetreatment chamber by a wall (bottom) in which openings are providedwhich are correlated with the exhaust connections of the fans and whichcorrespond in size to the exhaust connections of the fans. It is ofadvantage if the bearing surfaces of the conveyor belts are sealed,preferably at the sides in order to prevent the air and the fibers frombeing sucked off.

If a dryer with several superimposed conveyor belts is used, the dryermay be equipped with a device for reversing and for passing on the fiberfleece from one conveyor belt to the next one. Such a device may consistof an adjustable chute with a roller which is correlated to the conveyorbelt below. It is of special advantage if the material is passed onoutside of the treatment chamber. In case of such an arrangement theroller serves simultaneously for sealing the intake of the secondconveyor belt and/ or of the conveyor belt which is arranged below.

If the dryer is subdivided into several chambers, each chamber may forma treatment zone with varying treatment temperatures. In that case it isadvantageous to seal the point of passage of the material and of theconveyor belt from one chamber to the next one by means of a rollerwhich simultaneously serves for consolidating the fiber fleece.

Especially expedient is a device in which, within the predrying zone,sieve drums subjected to a suction draft are used as conveying elementsand in which at the point of passage of the fiber fleece from the sievedrums to the subsequent conveyor belt a roller is arranged which pressesagainst the fiber fleece and which consolidates it at the point ofpassage. The predrying zone or the dryer with sieve drums subjected to asuction draft may also be completely separated from the belt dryer. Inthat case it is of importance that the fiber fleece is not loosened upwhen being passed from the sieve drum dryer to the belt dryer, as is thecase usually up to now, but that the con solidated state is maintainedor produced anew.

Furthermore, it is of advantage if the conveyor belt is covered by afine wire mesh so that fibers cannot be sucked through the conveyorbelt.

The drawings illustrate some embodiments of the present invention.

FIGS. 1a and 1b are partial schematic views illustrating a carbonizingplant according to the present invention; whereby FIG. 1b should bethought of as placed along side FIG. la to illustrate the completeoverall installation.

FIG. 2 is a longitudinal cross-sectional view of a drying and bakingdevice according to the present invention;

FIG. 3 is a transverse cross-sectional view of the device according toFIG. 2; and

FIG. 4 is a longitudinal cross-sectional view of a modified embodimentof a drying and baking device according to the present invention.

Referring now to the drawing wherein like reference numerals are usedthroughout the various views to designate like parts, and moreparticularly to FIGS. 1a and lb, material 1 to be carbonized, preferablyraw wool, is fed in the installation illustrated in these figures into asuction drum bath. For acidifying the wool the treatment liquor may,e.g., consist of 3-6% sulphuric acid. Other carbonizing agents arehydrochloric acid or aluminum chloride. The bath proper is provided witha floating distance 2 at the intake and with a conventional sieve drum 3subjected to a suction draft at the delivery end. Along the floatingdistance the loose wool 1 can spread evenly over the whole workingwidth. The loose wool is then sucked onto the sieve drum 3 as a uniformfleece and is passed on to a pair of squeeze rollers 4 arranged behindthe sieve drum 3. Owing to the uniformity of the fleece, acidifying aswell as the squeezing effect are extremely uniform.

In the device shown in FIG. la, pumps 5 are arranged within the sievedrum 3 perpendicularly to the drum axis. The pumps 5 convey the suckedoff liquid into a duct 6 arranged above the same, in which duct theliquid is led out of the sieve drums 3 at the sides thereof, preferablyinto an open duct extending laterally along the whole treatment bathwhich open duct is connected with the treatment bath at the intake and/or along the entire length of the bath by conventional means. A furtherbath of that kind is connected behind the first one in the device shown.

The loose wool which has been pre-extracted by a second pair of squeezerollers 4 is then fed to a sieve drum dryer by means of a conveyor belt7. The dryer shown consists of a housing 8, which is subdivided by awall 9 into a treatment chamber provided with sieve drums 10 subjectedto a suction draft and into a fan chamber (not shown) with fan wheels(not shown) which are arranged at the end face of the sieve drums. Bymeans of partitions 11 the dryer is subdivided into a drying zone 12 anda baking zone 13. In the drying zone only one sieve drum is shown;however, two or more sieve drums may be used as well. Also in the bakingzone the number of sieve drums is not restricted to two sieve drums. Thenumber of sieve drums and the number of bowls depends essentially on therequired production capacity. The cellulosic matter in the wool iscarbonized in the baking zone 13.

For the removal of the carbonized matter an opener of conventionalconstruction is connected behind the dryer in this embodiment of theinvention, which opener consists essentially of a pair of feed rollers14 and of a spiked drum 15. Instead of the opener also a cardingmachine, a beating machine, or the like or a combination of suchmachines may be used.

For the neutralization of the sulphuric acid or of another acid used forcarbonization three bowls are provided which essentially are of the samedesign as the acid bowls, but which are equipped with three sieve drums3 connected one behind the other instead of with one sieve drum only andin which bowls a floating distance 2 is provided behind each sieve drum3. A pair of squeeze rollers 4 is provided also in this case at the endof each bowl. The first two bowls may contain an alkaline liquor forneutralizing the acid and the third bowl may be a scouring bowl with aneutral liquor. However, it is also possible that the first bowlcontains a neutral liquor and that only the second bowl contains analkaline liquor for neutralization. The latter combination offers theadvantage that part of the acid is washed out in the first bowl and thatless acid must be neutralized by means of neutralizing agents whichresults in savings of the neutralizing agents.

Final drying of the wool is again effected in a sieve drum dryer. Here,as in the case of the first dryer, the suction draft in the sieve drumis interrupted by conventional means at the portion of the sieve drumwhich is free from material, so that the drying air can only be suckedinto the sieve drum through the loose wool and the drying air iscompletely used for drying in each circulation cycle.

The belt dryer according to FIG. 2 has a housing 8 which is subdividedby a partition 11 into two treatment chambers 12 and 13. The twotreatment chambers 12 and 13 are separated by a bottom 18 from theappertaining fan chambers 19 and 29 which are arranged therebelow. Thetreatment chambers .12 and 13 are subjected to a suction draft by meansof bottom 18 and fans 21. The fans 21 thereby suck the air out of thetreatment chambers.

The air is passed through loose fibrous material 1 deposited on conveyorbelts 22 and 23. A pair of rollers 17 is arranged at the intake of thedevice which serves for sealing the intake and simultaneously forconsolidating the fiber fleece. Another pair of rollers 17' is providedat the point of passage of material 1 from the treatment chamber 12 tothe treatment chamber 13.

A chute 24 is used for passing on and for the simultaneous reversal ofmaterial 1 in fleece form. A roller 25 at the intake of the conveyorbelt 23 facilitates the formation of the fleece and consolidates thefleece.

FIG. 3 shows the circulation of the air in the dryer according to FIG.2. In a lateral duct 26 the air sucked out of the treatment chambers 12and 13 by the fans 21 flows over a heating device 27 into the treatmentchamber 12 or 13 respectively from above. Air guiding sheets 28 areprovided for a better air distribution.

The bearing surfaces of the two conveyor belts 22 and 23 are sealed bysheets 29 at the sides so that the total quantity of the air mustpenetrate the material deposited on the conveyor belts.

The drying device according to FIG. 4 consists of a treatment chamber 12provided with sieve drums 10; with one fan each (not shown) is providedat the end face-of each sieve drum 10 which sucks the air out of thesieve drums. In order to ensure that the air can enter the sieve drumonly along that portion which is covered by the material, baflle plates30 are provided along that portion of the sieve drum 10 which is notcovered by material. Owing to the powerful suction draft created in thesieve drums, the material on the sieve drums is only predried and thefleece is consolidated. In the following treatment chamber 13 a conveyorbelt 22 is provided as a conveying element. At the point of materialpassage from the sieve drum 10 to the conveyor belt 22, a roller 31 isarranged which presses onto or against the material and whichsimultaneously consolidates the fiber fleece. At the same time, thatroller seals the point of material passage. Since the fiber fleece,especially if it consists of raw wool and similar materials, is loosenedup during drying, another pair of rollers 17' may be provided after acertain drying distance. In general, the suction draft will, how ever,sufiice for holding the fiber fleece safely on a conveyor belt 22. Forthat reason the pair of rollers 17 is drawn in dashed lines.

Various conventional neutralizing agents may be used in the presentinvention to neutralize the acid, such as a soda solution, sodiumacetate, ammonia or the like.

While we have shown and described several embodiments in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to a person skilled in the art, and we therefore do not wish to belimited thereto but intend to cover all such 7 changes and modificationsas are encompassed by the scope of the appended claims.

We claim:

1. A continuous process for the carbonization of wool which compriseswetting the wool with an inorganic acid bath which is effective tocarbonize the wool but which does not adversely affect the wool quality,by conveying said wool through said bath on the surface of at least onesieve drum means while drawing the bath through said wool by means of asuction draft, drying the wool by conveying it on the surface of atleast one sieve drum means while drawing a heated treatment mediumthrough said wool by means of a suction draft, baking the wool similarlyas in said drying stage but at a higher temperature, opening the wool toremove the carbonized matter, neutralizing the acid adhering to the woolfibers by conveying it through an acid-neutralizing bath on the surfaceof at least one sieve drum means while drawing the bath through saidwool by means of a suction draft and finally drying said wool byconveying it on the surface of at least one sieve drum means whiledrawing a heated treatment medium through said wool by means of asuction draft.

2. The process of claim 1, wherein the inorganic acid bath is selectedfrom the group consisting of sulfuric acid, hydrochloric acid, andaluminum chloride.

3. The process according to claim 1, wherein the step of removing thecarbonized matter includes beating the wool.

4. The process according to claim 1, wherein after baking, theneutralization of the acid is effected in a gaseous atmosphere.

5. The process according to claim 1, wherein the step of neutralizingthe acid includes spraying the neutralizing agent onto the wool afterthe wool has entered a neutralization zone.

6. The process according to claim 1, wherein the wool is dryed in apre-drying zone and in a drying zone, and wherein the fiber fleece isexposed to essentially higher temperatures in the pre-drying zone thanin the drying zone.

7. The process of claim 1, wherein the wool is wetted with acid for aperiod of about 30 seconds.

8. The process of claim 1, wherein the drying and baking period extendsfor a period of about 3 to 5 minutes.

9. The process of claim 1, wherein the acid bath is a treatment liquorcontaining about 3 to 6% sulfuric acid.

10. The process of claim 1, wherein a floating Zone is provided in thewetting and neutralizing stages of the process.

11. The process of claim 1, wherein the wetted wool is squeezed toextract at least a portion of the acid bath contained therein.

12. The process according to claim 4, in which the gaseous atmosphere isa steam atmosphere.

13. The process according to claim 5, wherein the wool is wetted in theacid bath at a temperature below 20 C.

14. The process according to claim 13, wherein said temperature isbetween about 10 to 15 C.

References Cited UNITED STATES PATENTS 3,199,126 8/1965 Chaikin et al.68158 XR 3,374,646 3/1968 Fleissner 68l58 XR 3,410,119 11/1968 Fleissner68l58 XR FOREIGN PATENTS 683,080 11/1952 Great Britain.

OTHER REFERENCES Mizell et al.: Practical Improvements in WoolCarbonizing, American Dyestuff Reporter, Jan. 21, 1963, p. 51.

MAYER WEINBLATT, Primary Examiner US. Cl. X.R. 682, 158

